president barack obama and rowhani flying to south africa for this memorial. david cameron is joining was of the biggest meetings of global gatherings in recent history. the service is under way. joining us with more details, cnbc's chris fibber. chris. >> as you can see, the mining mag negligent and businessman who is tipped possibly to be the next president of south africa is doing the warm-up of the crowd, as it were. we're still waiting, we understand, for barack obama to arri arrive. he's on his way from victoria. bearing in mind that the roads are treacherous today. there's been heavy, heavy rain overnight which is seen in this continent as a blessing when a leader passes. we're going to be starting with speeches. it looks like the whole sort of ceremony is going to be delayed somewhat. the first hour will be family and friends. particularly, the first speaker will be andrew langheni. he was sentenced to life along with nelson mandela, and he will be giving the tribute. so everyone is looking forward to that. >> thank you very much, indeed, for that. tha